An LMA has been in use as an anesthetic administration device for several decades and is described in the U.S. Pat. Nos. 4,509,514; 6,422,239; 5,937,860; and 2,205,499. A standard LMA device is comprised of an airway tube and an elliptical shape mask with an inflatable cuff. An inflation line is attached to the outer aspect of the cuff to inflate or deflate the cuff with air. The distal end of the airway tube is attached to the back of the mask with an opening into the mask. This mask part of the device is then inserted into the pharyngeal cavity via the mouth of a patient under anesthesia. The cuff is inflated via the inflation line to create an adequate seal between the mask and the soft tissue of the pharynx. This mask sits above the vocal cords, such that the concave cavity of the mask is level with the laryngeal opening to maintain the patient's airway. The proximal end of the airway tube is outside the oral cavity, and is connected to an anesthesia breathing circuit to deliver oxygen and anesthetic gas mixture to facilitate anesthesia and maintain breathing during a surgery.
LMA devices have the disadvantage of not providing a complete seal of the airway; therefore, they are not the airway device of choice in patients who are at risk of aspiration, patients at risk of regurgitation of stomach contents into the trachea and lungs, or patients who need a complete seal of the airway for mechanical ventilation of the lungs. The endotracheal tube (ETT) is the preferred and most effective airway device for this group of patients. The ETT comprises a flexible tube with an inflatable cuff near the distal end and an inflation line that is attached to the cuff to inflate and deflate the cuff. Endotracheal intubation (ETI) comprises insertion of the ETT into the trachea through the laryngeal opening. Upon insertion, the cuff rests below the vocal cords and it is subsequently inflated with air via the inflation line to seal the trachea and provide protection against the passage of regurgitated stomach contents into the lungs. The proximal end of the ETT sits outside the mouth and is attached to the anesthesia circuit to deliver oxygen and anesthesia gas mixture to maintain anesthesia and ventilation of the patient. It can alternatively be connected to a mechanical ventilator to mechanically ventilate critically ill patients.
ETI is often performed via the aid of a procedure called laryngoscopy. This entails using a laryngoscope to view the vocal cords and laryngeal opening and subsequently insert the ETT into the trachea. The conventional methods of ETI can be difficult or impossible in some patients. In this subcategory of patients, a fiberoptic bronchoscope (FOB) is used to visualize the laryngeal opening to intubate the trachea with the ETT. This is a more skilled procedure and requires a conduit to guide the FOB and ETT to achieve successful endotracheal intubation. Since the cuff of the LMA in the patient's pharynx faces the laryngeal opening, the LMA is used as a guide to FOB visualization of the vocal cords, larynx and trachea. The FOB can thus be manipulated to pass through the laryngeal opening into the trachea. A well lubricated ETT is then threaded over the FOB in the trachea.
However, using the LMA device as a conduit has multiple limitations which diminish the success rate. Multiple modifications of LMA devices have been described in US patents over the past several decades (U.S. Pat. No. 4,509,519). Some of the past modifications to the LMA device have attempted to address the devices limitations. However, each solution introduced its own shortcoming, which in turn prevented these solutions from approval or widespread acceptance. There are two major problems with the LMA as a conduit for FOB guided endotracheal intubation:                (1) The ETT cuff is bulky, which makes its insertion into the airway tube of the LMA and subsequent threading of it through the airway tube into the trachea is challenging. Therefore, most of the time a smaller ETT is utilized, which is not ideal if long term ventilation is needed.        (2) LMA devices cannot be left in the patient for a prolonged period due to the risk of pressure injury to the soft tissue in the pharynx. To avoid pressure injuries, an LMA must be removed after the ETT is threaded into the trachea. However, the chance of dislodging the ETT during the LMA's removal remains high, since all existing LMA designs require the LMA being pulled out of the pharynx over the ETT.        
The invention addresses all the major limitations in this conduit technique and potentially provides a significant improvement in the success rate of ETT insertion and removal of the LMA after the ETT is in place, making it a near ideal conduit for FOB guided endotracheal intubation.